206606405989 has 2 divisors, whose sum is σ = 206606405990. Its totient is φ = 206606405988.

The previous prime is 206606405987. The next prime is 206606406023. The reversal of 206606405989 is 989504606602.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116356032100 + 90250373889 = 341110^2 + 300417^2 .

It is a cyclic number.

It is not a de Polignac number, because 206606405989 - 2¹ = 206606405987 is a prime.

Together with 206606405987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206606405987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103303202994 + 103303202995.

It is an arithmetic number, because the mean of its divisors is an integer number (103303202995).

Almost surely, 2^206606405989 is an apocalyptic number.

It is an amenable number.

206606405989 is a deficient number, since it is larger than the sum of its proper divisors (1).

206606405989 is an equidigital number, since it uses as much as digits as its factorization.

206606405989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5598720, while the sum is 55.

The spelling of 206606405989 in words is "two hundred six billion, six hundred six million, four hundred five thousand, nine hundred eighty-nine".